CATTLE INHERITANCE . I. COLOR' HEMAN L . IBSEN Kansas A gricdtural Experiment Station. Manhattan. Kansas Received January 31. 1933 TABLE OF CONTENTS PAGE ......................... 442 COLORGENES ................................................................... 442 Red, R ....................................................................... 442 Black, B ..................................................................... 443 Black Spotting, Bs ............................................................ 443 Modifiers: much black, M, little black, L ....................................... 444 Brindle, Br .................................................................. 445 Intensity and dilution: I and i; D and d ....................................... 447 Self and recessive white spotting, S and s ........................................ 448 Modifiers of s: little white, Lw, much white, Zw ....................... ......... 449 pigmented leg, PI, unpigmented leg, pZ ............................ 449 Roan, N ..................................................................... 451 Roan modifier, rm .... .................................. 454 Recessive white (Nellore cattle), ?evz ............................................. 455 Dominant white (Park cattle), W'p ............................................. 457 Dominant white spotting ....................................................... 458 1 . Hereford pattern, SH...................................................... 458 Modifiers: little white, Lw,much white, Zm ................................... 460 red neck. Rn. white neck rn ....................................... 460 red eye. Re. white eye. re ................................... 461 2 . Dutch belt. SD ........................................................... 463 3. Colorsided. Sc ............................................................ 465 4 . Inguinal white. In........................................................ 467 Whitening. w ................................................................. 468 Pigmented (black) skin spotting. Ps ............................................. 469 GENETICCOKPOSITION OB VARIOUSBREEDS ......................................... 471 Aberdeen-Angus........... .................................... 471 Holstein-Friesian.......... .................................... 473 Jersey ........................................................................ 474 Ayrshire ...................................................................... 475 Hereford ..................................................................... 475 Shorthorn .................................................................... 476 Guernsey..................................................................... 477 SOMATICCOLOR MUTATIONS ...................................................... 478 SUMMARY................. ........................................... 479 LITERATURECITED .............................................................. 479 Contribution No . 101. Department of Animal Husbandry . 1 feel greatly indebted to Profes- sors A. D . WEBERand H . W. CAVEand to other members of the Animal Husbandry and Dairy Husbandry Departments of the KANSASSTATE COLLEGE for much of the material about cattle breeds incorporated in this paper . After the paper was submitted for publication it was carefully read by Mr . EDWARDN . WENTWORTH,Director of Armour's Livestock Bureau, Chicago. who not only offered valuable suggestions for improvement in regard to the manner of presentation. but also submitted pertinent facts. based on his own observations. relating to the subject matter. Acknowledgment is hereby made of the editorial assistance rendered. and the new material used is credited in each case to Mr . WENTWORTHat its place of insertion in the paper . GENETICS18: 441 S 1933 442 HEMAN L. IBSEN INTRODUCTION A considerable amount of work has been done during the past fifteen years in the study of cattle inheritance. Each worker has taken up only a small portion, and no one has attempted to weld the whole mass into a compact whole. In this, and two other papers which are to follow, such an attempt will be made. The present paper discusses color inheritance, the second will deal with anatomical characters in general, and the third with milk production. In most of the published papers the effects of each gene have not been carefully defined. This naturally has led to confusion. The following pages will contain as nearly as possible an exact description of the effects pro- duced by each gene, together with its interactions, so far as they are known, with other genes. There probably is no truly logical order of gene presentation, but one sequence may lead to greater clarity than another. The one that seems most satisfactory will be followed here. The present series of papers is not intended to be to any extent historical, nor will much space be devoted to a discussion of the relative merits of conflicting theories. The main purpose is to outline the present status as it appears to the author. In the course of this presentation hitherto unpub- lished facts will be given, and factors will be postulated and described which have not as yet appeared in print. The complete, supporting data will not be presented here, but will be published elsewhere when time permits. COLOR GENES In the course of the present paper postulated color genes occupying nineteen different loci will be described in detail. Some of those included are given with a certain degree of hesitancy due to the meager evidence in support of them. Others, not included among the above, but proposed by various authors, will be mentioned chiefly to demonstrate that they do not actually exist. Each of the genes will be designated by means of distinctive letters, in order to avoid confusion; but, to prevent duplication, the letters proposed by the author making the first description of the character will not always be used. Red, R So far as we know, red (R)is present in all cattle. It does not always show because there are so many other genes epistatic to it. We shall there- fore have to assume for the present that it is always found in the homozy- gous condition, and consequently has no allelomorph. It causes the hairs to be red, and, when unaffected by other genes, is responsible for the brownish pigment in the skin of the nose and of the eyelids. INHERITANCE OF COLOR IN CATTLE 443 Black, B The gene for black (B),found in Aberdeen-Angus and Holstein-Friesians, causes all the pigmented hairs on an animal to become black. Besides hav- ing this effect, it is also responsible for the black pigment in the skin, hoofs, tongue, lining of mouth, eyelids, nictitating membranes and “whites” of the eyes, provided the white spotting gene (s) does not interfere. The relationship between B and s will be taken up when the latter factor is discussed. All that can be said concerning the allelomorph of black, 6, is that it is the absence of B. Animals that are bb are not necessarily red, although, as will be shown directly, this represents in part the composition of a truly red animal. Black Spotting, Bs Black spotting (Bs) refers to the type of black found in Jerseys and Ayrshires, and presumably also in Brown Swiss. All the pigmented hairs are not black, and the black is concentrated in certain areas, forming variable sized spots with a somewhat indefinite outline. Since the black is not completely extended over the pigmented part of the coat, red, which is always present, has an opportunity to show. Even in the black areas the hairs may not be entirely black. Besides having the above mentioned effect on the hairs, the Bs gene, like the B gene, causes black pigment to appear in the skin, hoofs, nose, tongue, lining of mouth, eyelids and “whites” of eyes, if the animal is a self (S). Another peculiarity of the Bs factor is that it is not fully expressed in the newly-born calf. Black pigment may be in the tongue and other parts above enumerated, but the black pigment in the hair creeps in gradually with increasing age, and males as a rule develop more black than the females. This sex-limited tendency will be discussed more fully under the factor pair M and L. AH that can be said concerning the recessive gene, bs, is that it is the absence of Bs. Since both B and Bs produce black hairs in one form or another, and since red (R)is always present, a bb .bsbs would be red, with no black hairs showing, unless other genes exist which cause black pigment to appear in the hairs. A bb bsbs animal should in addition be devoid of black pigment in the skin, hoofs, nose, tongue, lining of mouth, eyelids and “whites” of the eyes, provided it does not carry the gene Ps for pigmented skin. This gene will be taken up later. The Guernsey breed is usually of the composition bb bsbs. When Angus (BB) are crossed with Jerseys (BsBs) the offspring are black like the Angus, thus demonstrating that B is epistatic to Bs. Par- ticulars concerning the Fz of such a cross will be given after the factor for 444 HEMAN L. IBSEN brindling (BY)has been discussed. The interactions of B and Bs and their allelomorphs are as follows: BB BsBs, black BB bs bs, black bb Bs Bs, black-and-red bb bs bs, red PEARL(1913) and HOOPER(1921) have postulated a separate dominant gene for black tongue color in Jerseys. The former states in a footnote that further studies indicate that tongue color depends upon two separate factors which show partial coupling on a 3 : 1: 1: 3 basis. Both base their conclusions on herd book records.